Apparatus for stereophonic sound-recording



Feb. 9, 1954 H. FRIESS APPARATUS FOR STEREOPHONIC SOUND-RECORDING 4 Sheets-Sheet 1 Filed May 25. 1951 Feb. 9, 1954 H. FRIESS 2,668,880

APPARATUS FOR STEREOPHONIC SOUND-RECORDING Filed May 25, 1951 4 Sheets-Sheet 2 Z2 Z3 24' Z5 ,zizaa for Feb. 9, 1954 H. FRIESS 2,668,880

APPARATUS FOR STEREOPHONIC SOUND-:RECORDING Filed May 25, 1951 4 Sheets-Sheet s Feb. 9, 1954 H. FRIESS 2,668,880

APPARATUS FDR STEREOPHONIC SOUND-RECORDING Filed May 25, 1951 4 Sheets-Sheet 4 l l I I I do mama, a: awazb flwiz Patented Feb. 9, 1954 S YFOR STERE OPHONIC :SQUND-REGGRDING Hans Fries s, gKarlsruhe-J),

" fil WWP imi r ty, applicati fig May 26,1950

{This invention is concerned with a :m thod o and apparatus for stereophonim sounderecordins- "iIt. was customary heretofore, in stereophnnic sound recording, e. g., inthe ,productiqniof sound pictures, to make multiechannel recordings of individual production phases and record them upon carriers having at :least two sound :tra k which afterscutting ;-an d;comparing with the picture, were by. re-playing, and, mixing transcribed upon the player or production film. The pro.-

cedure requires .a iconsiderahle expenditure incident tothe production of the picture and in,-

cident to ,the required recording.

The invention proposes to simplify theproce- -dure.

' lit is.proposed, in accordanceswith the inven- .tion, to make amulti-channel recordings of certain production phases and single-channel -recordingstof .others, and to mix thesingle-channel recordings with the multi-channel recordings byibranchingrinto .a plurality of :channels to produce the production film. Multi-channel recordingwapparatus is. then required :for parts .of the scenes. or. production phases, e. a, or orchestral music, choirs .and mass scenes. Single-channel recording apparatus will sufiice fortsolo ,voices and generally :for speech and also for sound eifects.

Inithetbranchingof the single-channel recordings :to a plurality rofnchannels, the invention proposes .to .ad justably arrange the amplitude relationship of the sound :voltages in :these. channels. It is possible, in accordancelwith the inmention, to simulate incident to thesreproduction an apparent motion or clisplacementlofJthesound source inlateral direction, and similarly lby comlmon variationof the sound voltages in all channels .to simulate a idisplacementor. motion. of :the sounds inidepth.

'lhe various obiectsiof the invention will .now be explained by ,refierenceito .the accompanying drawings. In these drawings,

' Rigs. I-I'Sindicate in diagrammaticlmannenarrangements .of means lion practicing the new method;

Fig. ,4 shows in like (diagrammatic representation means employed in a re-play and mixing for raising .or loweringthe irequencies by amounts ofseveralrdb to obtain particular acoustic effects; and

Fig. :5, indicatesithe form ofa frequency curve that may he obtainedzbyuthe use ofiantiwdistor tion means incorporated inhliig. e.

Referringmow ltoe i'ig. 1:: there isrpro ided mul- ;tichannel; recording. apparatus comprising at include the required amplifiers and, a

he nelmcorfinsstoa nl-urality oichannels isiaccom elished :in a modified" manner. This 'particular least two microphones. I :and wh ch T ,911 nected with the- Qund-reoordins devices :3; and .4 by-wayiorthe usual transmission channels 'for smoothing out distortions and certain re lating means. The "sound-recording devices 3 audit may. ,be opticaleacoustioal recordin t rwices or :rnagneticsound erecordersor :Q iher equipmentisuitable iorrthecpurpose. {IS-he arrangement may be usedziorrecoltdingimaes scenes, o c est l music, choirs and the :like, and produces :upon the carrier .5 .two sound tracks.

In addition, there isproyided a single-channel recording apparatus fonsoloyyoicfis and sl efiC h, 'which compriscsqthe microphone 15 serving to record, through the medium of :the sound-record in; device 1, a. sound track upon it-hecarrier 3.

An additional-isinglephannelapparatus is provided which includes theymicrophone. ,8 andthe recordingideyice i0 for producing :a sound track upon thecarrier vvl ;l-,;s.o .as tov record, ,ior example, sound efiiects.

Q-After cutting and comparing, theearriers ,5, ,8, lil are scanned in a ne-play 'device by Suitable tonesscanning means 12-45; and are recorded uponi thertwo "sound tracks of :a carrier [=56 over a mixing device and 'by means of the recording apparatus 1| l, 118. The icarrier 1.6 serves as a production film or .asda :znaster for making. a production film.

'Ilhesingle-channel production phases scanned on the films :8 and M are upon re-playing hmnched-nyer the regulators 1H9, 2i] to the two channels comprising the recording apparatus H, 118. The amplitude relationship may be adiusted-in these. channels incident to, the mixing so as to create ran apparent :motion or displace- :mentof theisound source recordedin the single channels. Asidefrom'the regulators H11; 2;), there may :be prouidedmeans in the branch channels {or regulating therein thephase and, if desired, .also the frequency of the oscillations. It is possible in this manner tomake :the directional efiect moreenatural. Thechannels may also be ex- .chanscdiorl switchedincident to themising, e. g.,

hyvmeans loft aswitch diagrammatically indicated at 21 so as totsimulate particularly directional effects.

F H the; method: employing the arran ement Rig-:2,'thc'gbran h nsioithe ISiUgl1Qh3l11- soundtrack, tLQJDl'QdllQS shy branching-over the regulators I9, 20 and the sound-recording device 22-23 and 24-45, respectively, the intermediate films 2t, 21 each carrying two sound tracks. The recordings on these intermediate films 2 2'! are, after cutting and comparing, mixed with the recordings on the sound carrier 5 in a re-play apparatus and yield, as in Fig. 1, the common master or production film i6.

In the method according to Fig. 3, the produc tion phases obtained in the single-channel recordings with the use of microphones 6 and 9 are directly recorded by means of recording devices 22-232425, each upon two tracks, on the carriers 28, 29 by branching over the regulators i9, 28. The recordings on the carriers 28, 29 are then, by re-playing, mixed with the multi-channel recordings on the carrier 5 to obtain the master or production film id.

The invention is generally applicable-in soundrecording and sound transmission, e. g., in radio use or incident to transmission from one auditorium to another, and produces particular advan tages in the production of films. It is also applicable in the production of trick films and the like.

It is possible, by the use of a summation control ahead of the regulators IB20, to regulate the amplitude of the oscillations branching to the two channels while retaining their relationship, so as to simulate, e. g., apparent distance variations, that is to say, depth displacement of the sound source. The operation or adjustment may be facilitated by mechanical coupling'of the regulator and the summation control e. g., in such a manner that the adjustment of the control lever in one coordinate direction varies the total amplitude, while the relationship is varied incident to adjustment in the other coordinate direction. The sound source during the reproduction will then be subject to apparent shifting in accordance with the direction of adjustment.

Another object of the invention is to obtain, incident to the recording and/ or the mixing and re-playing, the raising or lowering, respectively, of certain frequencies within the tranmission range, especially in the median frequency range, e. g., at 2500 cycles, by amounts of several db. It is possible in this manner to vary upon reproduction the acoustic perspective, e. g., to particularly emphasize a voice as it leaves the loudspeaker. The invention provides for this pur pose regulable anti-distortion means, particularly in the mixing and re-play device. It is especially suitable to connect these anti-distortion means with the regulators and the summation control in such a manner that it becomes effective in the terminal positions thereof.

A re-play and mixing arrangement of this kind is diagrammatically illustrated in Fig. 4. The arrangement employs tape devices for the replaying carrying sound recordings upon the tapes 8, 5, II, respectively. The re-playing to the film 16 takes place in one operation. The regulators 1e, 28 include in their terminal positions the antidistortion means EB-29 and 3ii-3l, respectively, which therefore are switched in upon corresponding adjustment to raise or lower by several db the sound cu Tents of the median frequencies. The result is the impression that the voice or the sound effect is particularly prominently emphasized in one or the other direction; The summation controls 32, 33 and 34, 35 of the twochannel production phase, as well as the summation controls 36, 3'! of the shingle-channel recording may be provided with corresponding 4 anti-distortion means. Regulable anti-distortion means may be employed which are independent of the amplitude regulators.

The frequency curve indicated in Fig. 5 shows that a lowering or raising of the frequency may be obtained for the purpose stated, by the use of the anti-distortion means, within the median frequency range of 2500 Hz.

Changes may be made within the scope and spirit of the appended claims.

I claim:

1. Apparatus for producing stereophonic sound-recordings, comprising first carrier means, plural-channel means for recording predetermined production phases on at least two sound tracks of said first carrier means, separate second and. third carrier means, single-channel means for recording predetermined other production phases each respectively on a single track of said second and third carrier means, branch-channel means for each of said singlechannel recordings, and means for mixing the recordings of the branch-channel means with the recordings of said plural-channel mean to produce a final record having at least two sound tracks.

2. The apparatus as set forth in claim 1, together with means in each of said branch-channel means for regulating the amplitude relationship of the oscillations therein.

3. The apparatus as set forth in claim 1, together with means in each of said branch channel means for regulating the phase of the oscillations therein.

4. The apparatus as set forth in claim 1, together with means in each of said branch-channel means for regulating the frequency of the oscillations therein.

5. The apparatus as set forth in claim '1, together with means for selectively switching said branch channel means relative to said plural channel means.

6. The apparatus as set forth in claim 1, together with means for altering the frequencies in each of said branch-channel means by several db at a frequency range of about 2500 cycles.

7. The apparatus as set forth in claim 1, together with recording means cooperating with said mixing means, and oscillation regulation means in each of said branch-channel means.

8. The apparatus as set forth in claim 1, together with means in at least one of said channel means for adjusting the frequency of osciilations therein by several db at a frequency range of about 2500 cycles.

. 9. The apparatus as set forth in claim 1, together with anti-distortion means in at least one of said channel means for adjusting the frequency of oscillations therein by several db at a frequency range of about 2500 cycles, regulator and summation control means, said anti-distortion means being connected with said regulator and with said summation control means so as to effect its operative actuation at the terminal positions thereof.

10. Stereophonic sound-recording apparatus comprising a binaural sound carrier having two sound tracks, a pair of single-track carriers, recording and mixing means for combining the respective recordings on said single-track carriers with the recordings on said binaural carrier to form a record on a final carrier having two sound tracks, said recording and mixing means comprising two. main channel means for separately transcribing on the two tracks of said final carrier the recordings from the two respective sound tracks of said binaural carrier, and two branchchannel means for separately conducting oscillations from said single-track carriers to each of said main channel means.

11. The apparatusdefined in claim 10, together with means in each of said branch-channel means for regulating the oscillations therein.

12. The apparatus defined in claim 10, together with oscillation-control means in said main channel means.

13. The apparatus defined in claim 10, together with oscillation-control means in said main channel means and in said branch-channel means, respectively.

14. The apparatus defined in claim 10, tozether with means in each of said branch-channel means for regulating the oscillations therein, and means in said branch-channel. means for producing intermediate records from the respective recordings on said single-track? carriers. each of said intermediate records having two sound tracks.

HANS FRIESS.

References Cited in the file of this patent UNITED STATES PATENTS Camras July 24, 1951 

